The invention discloses an optical method and device for simultaneously measuring the direction, the sound intensity and the frequency of ultrasonic waves. The optical method comprises the steps that a dynamic ultrasonic phase grating formed by the ultrasonic waves in a liquid medium is lighted by a laser beam in the direction perpendicular to the propagation direction of the ultrasonic waves, and diffracted light forms a diffraction spectrum of the dynamic ultrasonic phase grating at an image surface of a lens; a hybrid photodiode array detector is arranged at the image surface of the lens, and the occurrence direction of the diffraction spectrum, the level 1 diffracted light intensity and the distance between adjacent diffraction spectrums are recorded; and the propagation direction, the sound intensity and the frequency of the measured ultrasonic waves are acquired through data processing. The optical device comprises a light source, an optical fiber, a lens, a lens base, sheet glass, a hybrid photodiode array detector, a detector base, a driving and scanning amplifying circuit and a computer, and is characterized in that a light emitting port of the optical fiber, the lens, the sheet glass and the detector are sequentially arranged, the detector is arranged on an imaging surface of the lens, and the driving and scanning amplifying circuit is connected with the detector and the computer.